Chassis control technology has achieved noteworthy progress, thanks to advancements in sensing and computing technologies as well as advances in estimation and control theory. This has permitted the design of various control systems using active means. One such enhancement is the control and adjustment of the tire forces through the braking force distribution control strategy, using a steering wheel angle sensor, a lateral accelerometer, and a yaw rate sensor to devise a yaw rate feedback control. Because the price of these different sensors is still high, this technology is limited to a small number of vehicles.
While a low cost implementation of this technology can be obtained by estimating the yaw rate and eliminating the yaw rate and/or lateral acceleration sensors, various operating conditions that are customarily inferred from the sensor information must be determined in some other way. One such operating condition is the bank angle of the road surface on which the vehicle is being driven. When operating on a banked road, the driver introduces a steering correction to maintain a desired course in spite of the bank, and the control should be compensated in these situations to avoid an unnecessary yaw rate command. For example, in a control described in U.S. Pat. No. 5,720,533 to Ghoneim et. al., and assigned to the assignee of the present invention, a bank angle compensation term is computed as a function of the sensed lateral acceleration. Accordingly, what is needed is a yaw control that compensates for bank angle without requiring a lateral acceleration sensor.